Downloaded from www.microbiologyresearch.org by IP: 54.70.40.11 On: Sun, 02 Dec 2018 09:23:01 Archaeoglobus sulfaticallidus sp. nov., a thermophilic and facultatively lithoautotrophic sulfate-reducer isolated from black rust exposed to hot ridge flank crustal fluids Bjørn O. Steinsbu, 1,2 Ingunn H. Thorseth, 1,2 Satoshi Nakagawa, 33 Fumio Inagaki, 4 Mark A. Lever, 54 Bert Engelen, 6 Lise Øvrea˚s 1,7 and Rolf B. Pedersen 1,2 Correspondence Bjørn O. Steinsbu bjorn.steinsbu@geo.uib.no 1 Centre for Geobiology, University of Bergen, Alle´ gaten 41, N-5007 Bergen, Norway 2 Department of Earth Science, University of Bergen, Alle´ gaten 41, N-5007 Bergen, Norway 3 Subground Animalcule Retrieval (SUGAR) Program, Extremobiosphere Research Center (XBR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Yokosuka 237-0061, Japan 4 Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Monobe B200, Nankoku, Kochi 783-8502, Japan 5 Department of Marine Sciences, University of North Carolina at Chapel Hill, 12-7 Venable Hall CB # 3300, Chapel Hill, North Carolina 27599, USA 6 Institut fu¨ r Chemie und Biologie Des Meeres (ICBM), Carl von Ossietzky Universita¨ t Oldenburg, Carl von Ossietzky Strasse 9-11, D-26111 Oldenburg, Germany 7 Department of Biology, University of Bergen, Jahnebakken 5, N-5007 Bergen, Norway A novel thermophilic and lithoautotrophic sulfate-reducing archaeon was isolated from black rust formed on the steel surface of a borehole observatory (CORK 1026B) retrieved during IODP Expedition 301 on the eastern flank of Juan de Fuca Ridge, eastern Pacific Ocean. Cells of the strain were lobe-shaped or triangular. The optimum temperature, pH and NaCl concentration for growth were 75 6C, pH 7 and 2 % (w/v), respectively. The isolate was strictly anaerobic, growing lithoautotrophically on H 2 and CO 2 using sulfate, sulfite or thiosulfate as electron acceptors. Lactate and pyruvate could serve as alternative energy and carbon sources. The G+C content of the genomic DNA was 42 mol%. Phylogenetic analyses of the 16S rRNA gene indicated that the isolate was closely related to members of the family Archaeoglobaceae, with sequence similarities of 90.3–94.4 %. Physiological and molecular properties showed that the isolate represents a novel species of the genus Archaeoglobus. The name Archaeoglobus sulfaticallidus sp. nov. is proposed; the type strain is PM70-1 T (5DSM 19444 T 5JCM 14716 T ). Growth by dissimilatory sulfate reduction is widespread among the Bacteria and is conducted by psychrophilic and mesophilic, as well as thermophilic, species (Castro et al., 2000; Shen & Buick, 2004). Among members of the Archaea, the only sulfate-reducers described so far belong to the genera Archaeoglobus and Caldivirga. In contrast to the sulfate-reducing bacteria, they thrive in hyperthermo- philic or extremely thermophilic conditions. The euryarch- aeote Archaeoglobus fulgidus was the first sulfate-reducing archaeon to be described and it was isolated from geothermally heated sediments at Volcano, Italy (Stetter et al., 1987). Later, the hyperthermophilic and acidophilic sulfate-reducing crenarchaeote Caldivirga maquilingensis was isolated from a hot spring in the Philippines (Itoh et al., 1999). The genus Archaeoglobus presently consists of four species with validly published names: A. fulgidus (Stetter et al., 1987; Stetter, 1988), Archaeoglobus profundus (Burggraf et al., 1990), Archaeoglobus veneficus (Huber 3Present address: Laboratory of Microbiology, Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Japan. 4Present address: Center for Geomicrobiology, Biology Institute, Aarhus University, 1540 Ny Munkegade, DK-8000 Aarhus C, Denmark. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain PM70-1 T is FJ810190. International Journal of Systematic and Evolutionary Microbiology (2010), 60, 2745–2752 DOI 10.1099/ijs.0.016105-0 016105 G 2010 IUMS Printed in Great Britain 2745